Evolution Explains Free Public Wi-Fi And Why Plants Make Drugs

Upon discovering earlier this week that McCarren Park became the first park in Brooklyn to offer free wi-fi, I was determined to take full advantage of the service. After finishing the workday, I’d make the short jaunt from Motherboard headquarters, pick up a 32-ounce to-go cup of beer from the bar next to the park, and settle in under a tree for some serious web surfing. Hell, I might have even pulled off writing this very column.

Then I realized I was being an ass. This whole internet thing is really, really addictive. Mix in beer and I’d be stuck there for hours. I might have never left. I’d posit that one day public wi-fi is going to create a new wave of young homeless who are so addicted to the information highway they can’t even manage to go home. This got me thinking.

Talking about the science of addiction would take a hell of a lot more space than I’ve got here, and to try to explain it from an evolutionary standpoint would be unnecessarily convoluted. Worse, the internet drug nerds that always seem to find such posts would be guaranteed to be nitpick it to death. Instead, let’s look at this from a different angle: why do plants make drugs in the first place?

The short answer is that plants, who aren’t particularly adept at running from predators, produce drug compounds for defense. In other words, plants produce nicotine, opiates and the like to be toxic. Before someone freaks out, saying that drugs aren’t poison, let me qualify that. First, what’s poisonous to an insect weighing a gram may also produce all kinds of good vibes in 180-pound me. Second, a chemical deterrent doesn’t have to be deadly to be effective – you probably aren’t regularly eating peyote flowers in your dinner salad, right?

The best example of plants’ chemical defenses is the alkaloid group. Alkaloids are all nitrogen-containing compounds. Many of them have pharmacological effects on humans. That includes just about everything that ends with ‘-ine’: nicotine, caffeine, morphine, mescaline, cocaine and so forth.

Dan Janzen, a legend who literally wrote the book on Costa Rican ecology, built a large body of work studying the correlation between toxicity and predation in alkaloid-producing plants. He found that certain plant species were basically untouched by insect predators during seed-bearing periods. Surprised that the tasty seeds were being left alone, Janzen found that those plants became more toxic while growing seeds. That chemical protection proves effective.

It’s important to note that humans aren’t immune. Jon Krakauer, in Into the Wild, suspects that the death of young adventurer Chris McCandless was due to eating legume seed pods at the height of the plants’ toxicity after having eating the plants’ roots for weeks without trouble. Krakauer quotes John Bryant, a chemical ecologist at the University of Alaska, Fairbanks:

What happens with a lot of legumes is that the plants concentrate alkaloids in the seed coats in late summer, to discourage animals from eating their seeds. Depending on the time of year, it would not be uncommon for a plant with edible roots to have poisonous seeds. If a species does produce alkaloids, the seeds are where the toxin is most likely to be found.

This serves to highlight a valuable point that’s oft overlooked: Nature in general is often viewed as being a vibrant, violent interplay of animals eating and evolving in competition with each other that plays out with a static green background of plants. That’s hogwash. Plants are just as murderous as any animal, evolving new chemical and physical defenses to outcompete (or simply kill off) other plants and prevent themselves from being eaten.

It’s the original evolutionary arms race. For example, giraffes love Acacia trees. Unfortunately, the Acacias are thorny. So giraffe tongues got longer—or, more correctly, giraffes with long tongues were better able to eat, and thus make more of themselves—as did Acacia thorns. The same process is happening constantly, with animals evolving immunity to plant toxins and plants constantly evolving new toxins to ward off animals.

Which, in a very roundabout way, takes us back to the very beginning. The fact that some plant compounds have pharmacological and/or psychotropic effects on humans is, in a way, random chance. In other words, while there is evolutionary pressure for plants to create toxins, there isn’t much natural pressure for plants to produce compounds that fuck us up (although marijuana’s increasing strength over the years is an interesting example of artificial pressures being applied through breeding).

In that sense, our love for certain drugs is partly a quirk of ecological systems that are constantly in flux. The compounds in a coca leaf may have evolved to ward off bugs, but it also happened to hit all the right chemical buttons for the first human who chewed on one and couldn’t get enough. It’s like happening upon wi-fi in a park: Sure, it’s there for some reason, but what’s notable is that once you get a hold of it, you can’t get enough.

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